For the purpose of preventing various inconveniences caused by microorganisms and infections, it has been a conventional practice to carry out a disinfection treatment on the surfaces of hard articles (food packaging containers, beverage containers, tableware, and the like).
There are a large number of methods for the disinfection treatment method, and one of them that is known is a disinfection method of washing the aforementioned surfaces by using a disinfectant composition containing an oxidizing agent. In general, oxidizing agents lose their disinfecting power when reduced; therefore, oxidizing agents are suitable from the viewpoints of handling after use and safety.
Examples of the oxidizing agents that may be used include chlorine-based oxidizing agents such as sodium hypochlorite, ozone, and oxygen-based oxidizing agents, and as the oxygen-based oxidizing agents, hydrogen peroxide, or inorganic peroxides that generate hydrogen peroxide in water, such as sodium percarbonate, are used. In order to increase the oxidation action (disinfection action), the oxygen-based oxidizing agents are usually used in combination with alkali agents such as sodium carbonate.
Among these, methods using chlorine-based oxidizing agents may cause off-flavor and off-smell after a disinfection treatment (for example, the off-flavor and off-smell originating from a chloride of a resin that is produced when a hard surface made of a resin is treated), and methods using ozone have problems such as an increase in the capital investment due to the introduction of an ozone generator, and a risk of health hazard to the operators caused by an increase in the ozone concentration in the washing environment. Accordingly, oxygen-based oxidizing agents are preferably used for the disinfection of the surfaces of hard articles such as tableware and packaging containers.
In recent years, while the preference to hygiene is increasing, there is a strong demand for an increase in the disinfecting power of the disinfectant composition. However, oxygen-based oxidizing agents have insufficient disinfecting power even if used in combination with alkali agents, and have problems such as proliferation of microorganisms caused by the lack of disinfecting power, and consequent generation of off-flavor and off-smell. Furthermore, If the amount of the alkali agent that is used in combination is increased, there is also a problem that the alkali agent is likely to adhere to the surfaces of hard articles such as food packaging containers to be treated, or to the inside of a washing machine used for the disinfection treatment. In regard to these problems, it has been suggested to use an organic peracid precursor such as sodium 4-dodecanoyloxybenzenesulfonate, or a metal compound such as a copper salt or a manganese salt in combination, for the purpose of enhancing the disinfecting power of oxygen-based oxidizing agents.
Among these, metal compounds have a function of increasing the oxidation action of hydrogen peroxide as an oxidation catalyst and increasing the disinfecting power. However, when a metal compound is incorporated, the disinfecting power is increased, but there is a problem that hydrogen peroxide is likely to undergo hyperdegradation in water, and the residual time is short. In regard to such a problem, a method of combining a metal compound with a specific chelating agent has been suggested. For example, Patent Literature 1 suggests a combination of a specific chelating agent and a copper salt as an oxidation catalyst for disinfection and bacterial elimination. Furthermore, Patent Literature 2 suggests a composition for disinfection and bacterial elimination prepared by granulating a copper salt together with a binder compound, and mixing this with a peroxide, a specific chelating agent, an activating agent, a surfactant and the like.